fix: Explain queries should always return as an array of results

[cbaker6]

Requires a server fix parse-community/parse-server#7440. The discussion parse-community/parse-server#7442 has more information.

• Add support for an array of objects when using find by updating testcases. This falls inline with the rest of query results
• Adds support to explain a first query which was previously not available in the JS SDK

[parse-github-assistant]

Thanks for opening this pull request!

• ❌ Please link an issue that describes the reason for this pull request, otherwise your pull request will be closed. Make sure to write it as Closes: #123 in the PR description, so I can recognize it.

[mtrezza]

Mergeability depends on discussion parse-community/parse-server#7440 (comment).

[parse-github-assistant]

I will reformat the title to use the proper commit message syntax.